1. Field of the Invention
The present invention relates to fluid drain structure at the bottom of beds of media through which the fluid passes. More particularly, the invention relates to placing conduit segments of a manifold for the fluid in the lower portion of the media bed with distribution perforations in the segments isolated from the media so the media is not bearing directly on, or over, the apertures.
2. Description of the Prior Art
Beds of granular media are commonly placed inside vessels and fluids passed through the media. Most of such units are more or less simple filters to remove undesirable material from the fluid. However, there are many different materials to be removed from fluid streams and many different materials useful as bed media.
The problem of present concern is in distributing fluid over the horizontal face of the media bed. The prior art is replete with distribution systems whose essential elements are plates with spaced apertures or porous bodies. These perforated plates and porous bodies are usually placed to span their vessel containing the media near its bottom. Fluid is conducted into, or removed from, the vessel below the plate and bodies.
In the prior art, the media bed has rested directly over and on the plate openings of porous bodies. The bed is supported by the plate or body structure. Of course the particles of media must be sized larger than the holes in the plate or porous bodies or the particles will pass through the holes and be lost downstream. If there is a rupture of the plate, its holes enlarged accidently, or the media particles fragmented, media will be lost. It is desired, therefore, that the media be supported but not have direct contact with distribution apertures for fluid. Rupture of porous support structure for the media should not result in direct loss of media particles downstream of the vessel from the media bed. All improvements to support structure should improve fluid distribution horizontally over the cross section of the bed with structure which is simple to fabricate and assemble.